CIRCUIT TO DETECT AND TEST LIGHT SIGNALS Russian patent published in 2002 - IPC

FIELD: control over light signals on railroads. SUBSTANCE: control relays without forced make or break of switching contacts are used to switch on lamps of reliable light signal instead of signal relays. Control relays are so structurally designed that individual switching contacts while frozen together in one position will not be any more thrown over when reversed. Contacts are so placed in feeding lines of signal lamps that mechanical fixation of one contact is displayed at the latest under load following onset of this defect thanks to subsequent process of setting. It takes place due to fact that corresponding signal lamp can not be cut in any more and that certain test messages are missed. EFFECT: enhanced functional reliability of circuit. 9 cl, 6 dwg